Why is speed important for an airplane?

Answer 1

Because the more speed of the air under the wings, can produce better upward force. The wings are designed for produce more pressure of air under the plane, and when the pressure increases, it forces the plane to go up and fly. If you note the big Boing or Airbus planes, they had an accessory inside the wings which is used extended only in low speed, to increase the area of the wings and produce more force of the less air pressure they had at low speeds. When the planes had take-off, the wings are shortened, because the speed is increasing and the pressure with a short wing is enough to sustain the plain easy. At the landing, again the plane is forced to speed down and extend the wings to produce more sustain while landing and the velocity is decreasing. Some jets has the hability to change the angle of their wings by the same reason, when they are at the low speed their wings are completened open, and when they are at the higher speeds, the wings close and with less area they can plane easy and with less atrict and economy of fuel.